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  • Author or Editor: T. Tominaga x
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Abstract  

Eu-151 Mössbauer spectra of tetrakis/diethyldithiophosphato/europium/III/ compounds suggests substantial electron transfer from dithiophosphate ligand to europium. The photochemical reaction of these complexes was investigated in organic solutions, and it was demonstrated that the Mössbauer isomer shift was correlated with their 420 nm band.

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Abstract  

Seven REEs in the deep sea sediments from various regions /19 sites/ of the Pacific Ocean and the Japan Sea were determined with INAA. Regional variations of La/Yb ratio and Ce anomaly may reflect the relative contribution of the source materials in the formation of the deep sea sediments.

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Abstract  

The UV photolysis of pentacarbonyliron isolated in low temperature nitrogen matrix by continuous or pulsed deposition was studied by means of Mössbauer technique. Unstable species such as Fe/CO/n /n=2–4/ were produced by UV irradiation and their Mössbauer parameters were measured. The yields of unstable species were found to be influenced by the deposition method of nitrogen matrix.

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Abstract  

Molecular orbital calculations were performed to obtain electron density and electric field gradient at the iron nucleus of iron carbonyls Fe(CO)n (n=2–5) so as to estimate the Mössbauer parameters, of these species. The calculated values were compared with the experimental values obtained in low temperature nitrogen matrices; structures of these species were optimized to fit the observed values.

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Abstract  

The UV-induced photochemical reactions of pentacarbonyliron with ethene in a low temperature nitrogen matrix were studied by means of the Mössbauer technique. Fe/CO/4/C2H4/ was produced by UV-irradiation of penfacarbonyliron in close proximity to ethene molecules in a pure ethene matrix, or a homogeneous cocondensed matrix. The other products were obtained via thermal reactions with ethene of Fe/CO/4 trapped in stratified matrices.

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Abstract  

Molecular orbital calculations have been performed to obtain the electron density and electric field gradient at the iron nucleus of tetracarbonylethene iron Fe(CO)4(C2H4) produced by UV-irradiation of pentacarbonyliron cocondensed homogeneously with ethene in a low temperature matrix, so as to estimate the Mössbauer parameters of the species. Mössbauer isomer shifts and electron densities at iron nuclei (O) of Fe(CO)n (n=5,4,3,2) as well as Fe(CO)4(C2H4) are discussed: they have fairly good linear relationship to give –0.27 mm/s/aO –3. An isomer of Fe(CO)4(C2H4) produced via thermal reactions of Fe(CO)4 with ethene in a stratified matrix is discussed by comparing the calculated and observed Mössbauer parameters.

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Abstract  

By means of INAA, REEs in the dredged rocks from a seamount /KH73-4-2/ in the East Mariana Basin were determined. Based on the REE patterns, the rocks are classified into two groups despite of alteration: highly altered palagonite of oceanic-island tholeiitic nature, and relatively fresh basaltic-andesitic rocks of alkaline rock nature.

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Abstract  

The60Co hot atom reactions were studied in tris/acetylacetonato/cobalt/III/ adsorbed on silica-gel surface.57Fe Mössbauer spectra of tris/acetylacetonato/iron/III/ in the corresponding system were also measured in order to examine the state of dispersion of complex molecules on silica-gel. The retention formation processes were discussed in terms of the dependence of60Co retention on the adsorbed amount /concentration/ of cobalt/III/ complexes.

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Abstract  

Mössbauer spectra of hexakis/alkylurea/iron/III/ complexes were measured to investigate the paramagnetic relaxation in ionic compounds. The effects of iron-iron distance and temperature on Mössbauer line shape were studied in these compounds, and the results are discussed in comparison with our previous data on tris/\-diketonato/iron/III/.

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Abstract  

Unstable novel species produced by photolysis of ferrocene (Cp2Fe) isolated in low-temperature matrix were studied by means of the57Fe Mössbauer spectroscopy. On the UV-irradiation of57Fe-enriched ferrocene co-condensed with CCl4 in low-temperature N2 matrix (20 K), unknown high spin ferrous species (I.S.=0.90±0.01 mm/s, Q.S=1.94±0.02 mm/s) were produced as well as ferricinium ion [Cp2Fe]+ (I.S.=0.52±0.01 mm/s, Q.S.=0.0 mm/s). On the annealing, these photoproducts disappeared to reform ferrocene by the reverse reaction in the matrix. The mechanisms of the photochemical reaction were discussed.

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